* checks.adb (Insert_Valid_Check): Code cleanup.
* exp_ch6.adb (Add_Validation_Call_By_Copy_Code): New routine.
(Expand_Actuals): Generate proper copy-back for a validation
variable when it acts as the argument of a type conversion.
* sem_util.adb (Is_Validation_Variable_Reference): Augment the
predicate to operate on type qualifications.